playtaya.blogg.se - Gis perform intersect with vector and raster

#GIS PERFORM INTERSECT WITH VECTOR AND RASTER HOW TO#
#GIS PERFORM INTERSECT WITH VECTOR AND RASTER INSTALL#
#GIS PERFORM INTERSECT WITH VECTOR AND RASTER CODE#

We will have a graphical look at the different results along the way using OpenJUMP. We will import the shapefile and the raster coverage into PostGIS, create buffers around each point and then intersect those buffers with the elevation coverage in order to get a weighted mean elevation for each buffer. You can find a pretty good description of this dataset in Wikipedia ( ). Just download ten of them in the area of your choice. You do not have to download the same files we used. These free rasters, available on the web, are 6000圆000 pixels each, have a pixel size of about 60 x 90 meters and weight a total of 900 MB once unzipped.

The second dataset is a series of 13 SRTM elevation rasters covering most of the province of Quebec.

We will show later in the tutorial how you can easily produce a similar random point cover.

The first dataset is a point shapefile of 814 caribou observations done by airplane in the northern part of the province of Quebec by the provincial ministry of natural ressources between 19.

GDAL 1.6 for Python 2.6 (or GDAL 1.6 for Python 2.5).

GDAL 1.6: You will have to compile it before WKT Raster.

#GIS PERFORM INTERSECT WITH VECTOR AND RASTER CODE#

WKT Raster: We compiled the last code available.

#GIS PERFORM INTERSECT WITH VECTOR AND RASTER INSTALL#

Refer to the readme file of each software to install them properly. We assume that PostgreSQL, PostGIS with WKT Raster are well installed. We will describe the steps mainly on Windows, but Linux gurus will have no problem writing the equivalent commands in their favorite OS. You can do this kind of analysis pretty easily in any GIS package but what is special here and not easy to do in ANY GIS package is the size of the datasets involved (900 MB of raster data), the simplicity of the queries and the speed at which we will get the results. Note also that "gdal2wktraster.py" has been renamed "raster2pgsql.py" in PostGIS 2.0.īasically the problem introduced in this tutorial is to compute the mean elevation for buffers surrounding a series of point representing caribou observations. NOTE: Since its integration into PostGIS 2.0, PostGIS WKT Raster is now simply called "PostGIS raster".

is not only a raster format but a SQL raster manipulation and analysis API.

comes with a very versatile Python raster loader (supporting batch loading through wildcards and as many input formats as GDAL does).

is very well integrated with the existing PostGIS geometry type allowing for example seamless and efficient intersections operations with vector tables.

is not really limited in size (PostgreSQL has a limit of 32 TB).

supports multiband, nodata value, georeference, overviews, overlapping tiles and non rectangular coverages.

is the raster format introduced by PostGIS.

You will get more info on PostGIS WKT Raster in this page but we can say that WKT Raster.

#GIS PERFORM INTERSECT WITH VECTOR AND RASTER HOW TO#

Mấy nay đau đầu với cái này nên note lại tutorial will show you how to do a very classical raster/vector overlay analysis with PostGIS WKT Raster. PostGIS WKT Raster Tutorial 1 - Intersecting vector polygons with large raster coverage using PostGIS WKT Raster